SigmaHQ/rules/linux/macos_binary_padding.yml

title: 'Binary Padding'
id: 95361ce5-c891-4b0a-87ca-e24607884a96
status: experimental
description: 'Adversaries may use binary padding to add junk data and change the on-disk representation of malware. This rule detect using dd and truncate to add a junk data to file.'
    # For this rule to work you must enable audit of process execution in OpenBSM, see
    # https://osquery.readthedocs.io/en/stable/deployment/process-auditing/#macos-process-socket-auditing
author: 'Igor Fits, Mikhail Larin, oscd.community'
date: 2020/10/19
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1027.001/T1027.001.md
logsource:
    product: macos
    category: process_creation
detection:
    selection1:
        Image|endswith:
             - '/truncate'
        CommandLine|contains:
             - '-s'
    selection2:
        Image|endswith:
             - '/dd'
        CommandLine|contains:
             - 'if='
    filter:
        CommandLine|contains: 'of='
    condition: selection1 or (selection2 and not filter)
falsepositives:
    - 'Legitimate script work'
level: high
tags:
    - attack.defense_evasion
    - attack.t1027.001